particle.h

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//            Copyright (C) 2004-2007 by The Allacrost Project
//                         All Rights Reserved
//
// This code is licensed under the GNU GPL version 2. It is free software 
// and you may modify it and/or redistribute it under the terms of this license.
// See http://www.gnu.org/copyleft/gpl.html for details.

/*!****************************************************************************
 * \file    particle.h
 * \author  Raj Sharma, roos@allacrost.org
 * \brief   Header file for particle data
 *
 * This file contains structure(s) for representing a single particle. In theory,
 * we should be able to just have one structure which holds all properties for
 * a particle, but in fact we have two: one for the position, and one for everything
 * else. The reason is that having the positions separated is more efficient
 * for rendering.
 *****************************************************************************/

#ifndef __PARTICLE_HEADER__
#define __PARTICLE_HEADER__

#include "defs.h"
#include "utils.h"
#include "color.h"
#include "particle_keyframe.h"


namespace hoa_video
{

namespace private_video
{


/*!***************************************************************************
 *  \brief this is used in the vertex array for DrawArrays(). Every time
 *         the particle system is rendered, we need to iterate through all the
 *         particles in the system, and use the position, size, and rotation
 *         to generate 4 ParticleVertex's. This is pretty expensive, but
 *         unfortunately it's necessary since the positions change every frame.
 *****************************************************************************/

class ParticleVertex
{
public:

  float _x;
  float _y;
};


/*!***************************************************************************
 *  \brief this is used in texture coordinate array for DrawArrays()
 *         Unless animated particles are used, this can be generated just once
 *****************************************************************************/

class ParticleTexCoord
{
public:

  float _t0;
  float _t1;
};


/*!***************************************************************************
 *  \brief this is the structure we use to represent a particle
 *****************************************************************************/


class Particle
{
public:

  float  x;
  float  y;
  
  float  size_x;
  float  size_y;
  
  float  velocity_x;
  float  velocity_y;
  
  float combined_velocity_x;
  float combined_velocity_y;
  
  Color  color;
    
  float  rotation_angle;
  
  float  rotation_speed;
  
  float  time;
  
  float  lifetime;
  
  float wave_length_coefficient;  
  
  float wave_half_amplitude;

  float acceleration_x;
  float acceleration_y;
  
  float tangential_acceleration;
  
  float radial_acceleration;
  
  float wind_velocity_x;
  float wind_velocity_y;
  
  float damping;  
  
  float rotation_direction;
    
  float current_size_variation_x;
  float current_size_variation_y;
  float next_size_variation_x;
  float next_size_variation_y;  
  float current_rotation_speed_variation;
  float next_rotation_speed_variation;  
  Color current_color_variation;
  Color next_color_variation;
  
  ParticleKeyframe *current_keyframe;
  ParticleKeyframe *next_keyframe;
};

}
}

#endif  

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